1. Technical Field
This invention relates to railroad rail cars and more specifically to sliding rail car doors that are used to gain access to the rail cars. Wheeled carriages are used to support the doors and allow for sliding action along a guide and support track mounted on the lower doorsill of the boxcar.
2. Description of Prior Art
Prior art devices of this type have relied on wheel carriage housings to act as bearing guide surfaces. The wheeled carriage housings are cast with a reinforced wear surface area within that selectively engages the respective sides of the guide track holding the carriage assembly wheels on the track, see for example U.S. Pat. No. 3,106,000 drawn to rollers for door of refrigeration and box cars. Other prior art patents have disclosed various roller guides utilized in other art applications, see for example U.S. Pat. Nos. 3,033,285, 3,956,857, 4,064,592, 4,457,046, 4,633,615 and 5,165,142.
All of the above referred to patents show a variety of different wheel track configurations most of which are drawn to analogous art of sliding doors, such as patio doors set forth in U.S. Pat. No. 4,633,615, sliding panels with an assembly showing rollers, a support track and guide element set forth in U.S. Pat. No. 4,639,970. Examples of track engagement guides associated with roller slide assemblies can be seen in U.S. Pat. No. 3,033,285 on a track and roller combination for sliding screen doors and in U.S. Pat. No. 3,956,854 on an apparatus for preventing detachment of horizontal rolling sashes of a window or the like.
Most of the devices have a wheeled carriage which is engageable on a track and utilizes secondary structures extending from the carriage to hold the carriage onto the track by selective frictional engagement on either side of the track as the doors move longitudinally therealong.
Applicant""s device is directed towards railroad car door assemblies in which carriages are used to support a door and portions of the carriage housing are used as a retaining means against the guide track on which the rollers engage.
This invention is directed towards rail car doors track retaining devices wherein a wheel support carriage slideably engages a door support track on which the rail car door slides. Wear guide inserts of the invention are removably secured within the carriage housing at points of track engagement providing a self-lubricating synthetic resin slide bearing surface for the carriage.